Pittsburgh Ballet Theatre presents it free “Ballet Under the Stars” show Aug. 21 at Hartwood Acres’ Middle Road concert area, Hampton Township, Allegheny County. The performance includes a Johnny Cash tribute and new work by PBT dancer Cooper Verona. The evening begins with free children’s activities from 5 to 7 p.m. and a ticketed barbecue dinner at 5 p.m. The free mixed repertory performance starts at 7:30 p.m. Dinner tickets are available by calling 412-454-9138.